After the story telling you’ll get the option to add one more team member who comes with you and Barrett. If you want to take the Materia off one of your old team members and give it to Barrett you can. Just talk to the other team members that are still standing in the house to bring up the team reformation window as many times as you'd like.

Take your new team and head back up north where you started.  Keep going north until you arrive at the screen seen on the right (the one with the fence).

Go north and through the opening on the fence and then go right. When you arrive at the screen to the right you should set up Barrett so that he can fight alone. Make sure he has some half decent armor and his best weapon equipped. For the fight against Dyne you’ll mostly be relying on attacks and limit breaks and the odd heal Barret when he gets low. Equip Barrett with non-magic Materia, no summons or MP using spells. Equipping this type of Materia reduces his Max HP among other important stats. Equip him with some yellow Materia though. Even if you’re not using the actual moves (like Steal and Throw) you can still benefit from the extra stats they add. Also make sure that the “important” Materia that Barrett is equipping (especially Restore) is equipped on Barrett’s new W Machine Gun as opposed to his armor. W Machine Gun has double growth rate so don’t waste that spot on Materia that doesn’t really need to grow.

Now, after that long-winded explanation, go around the truck and continue north following the trail to find Dyne.

Tips and tricks for Chocobo racing:

- First and foremost: choose manual steering. Even if you’re bad at it, take these opportunities to get good as they’re given to you. Pressing select puts you in manual control.

- Press square a bunch of times to get your Chocobo running as fast as possible.

- Don’t waste too much energy at the beginning of the race. Save it for the final stretch. Anywhere near the space section of the course will do. Don’t get too far behind but don’t worry about staying No. 1 the whole time.

- Hold down R1 and R2 to slowly refill your stamina. Pretty much a cheat, but since there are no downsides and you can use this every time, you might as well use the advantages you’ve been given.

If you lose the race you’ll get a faster Chocobo and get to try again. Nothing bad happens if you lose either, so take a few tries if needed.

Your reward for successful completion is the buggy!